"a furtive manner" "a sneak attack" "stealthy footsteps" "a surreptitious glance at his watch"
"backstairs gossip" "his low backstairs cunning" "backstairs intimacies" "furtive behavior"
The students made furtive drawings, or passed notes.
There was nothing furtive about his going in: he entered boldly and directly.
牛津高阶第八版
美国韦氏词典
Dictionary.com
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维基百科 (自由的百科全书)